/Engine/Source/Developer/CookedEditor/Public/CookedEditorPackageManager.h
Meat of this class, this calls other functions that generally will be overridden - subclass needs to pass in disabled plugins
void GatherAllPackagesExceptDisabled ( [TArray](API\Runtime\Core\Containers\TArray)< [FName](API\Runtime\Core\UObject\FName) > & PackageNames, const [ITargetPlatform](API\Developer\TargetPlatform\Interfaces\ITargetPlatform) * TargetPlatform, const [TArray](API\Runtime\Core\Containers\TArray)< [FString](API\Runtime\Core\Containers\FString) > & DisabledPlugins ) const